The new baby is now fourth-in-line to the throne, behind brother George, father William and grandfather Prince Charles.

Everyone below the new royal baby will move down a place, starting with William’s brother Prince Harry who will drop to fifth position.

In celebration of the birth, cannons will be fired across London in celebration – 62 shots from the Tower of London and 41 from Green Park – and the Union Jack flag will be flown from government buildings across Britain.

Fashion princess

Experts say the royal birth could inject tens of millions of pounds (euros, dollars) into the British economy, with a baby princess particularly lucrative because she could become a fashion trendsetter.

George’s birth gave Britain a £390 million (S$785 million) boost and the new baby is expected to generate approximately £300 million, according to figures from the London School of Marketing.